A Williams Bros. 2 1/2 inch pilot ought to fit the Spitfire just fine, I think the scale is 1/9. Hangar 9 also makes some nice pilots in that size, they are little more expensive, though.

Monocote can be painted. Cover the airplane with the lighter of your two colors (either tan or gray, depending on your scheme) then clean the surface really well with alcohol. Scuff it lightly with 00 steel wool, mask off your pattern with some cheap shelf paper, and then paint with either Lustrecote (follow the directions!!) or Rustoleum. Let the paint cure for about a week before exposing to glow fuel and then go fly.